Pulse-signal translating system



Jan. 5, 1954 R. B. J. BRUNN PULSE-SIGNAL TRANSLATING SYSTEM Filed March 26, 1949 ATTOR NEY Patented Jan. 5, l1954 2,665,378 PULSE- SIGNAL TRAN SLATIN G SYS TEM Robert B. J. Brunn, Manhasset, N.

Hazeltine Research, Inc.,

ration of Illinois Y., assignor to Chicago, Ill., a corpo- Application March 26, 1949, Serial No. l83,658

(Cl. Z50- 27) 17 Claims. 1

The present 4iu'zention relates, in' general, Ato pulse-signal translating systems and, particularly, to systems for translating `applied desired pulses which have a predetermined pulse duration while discriminating against applied undesired pulses, at least a portion of each of which has a pulse duration less than the aforesaid predetermined duration. Such systems are highly receptive or selective to pulses having a prede- -termined mean pulse fundamental frequency but are capable of substantially rejecting pulses having other mean frequencies. While the invention is subject to a variety of applications, it is especially suited for use in the pulse-signal receiver of distance-measuring equipment in which the distance information is produced by means of wave-signal pulses, and it will be particularly described in that connection.

In pulse-signal translating systems, it is often desirable to distinguish a desired group of pulses having predetermined frequency characteristics from pulses having different frequency characteristics or different phase relationships. For instance, in order to increase the selectivity or response of a receiver to pulses that are received from beacons used with a distance-measuring equipment system from pulses received from other pulse-modulated equipment operating on adjacent carrier frequencies, it is necessary to employ circuit means for selecting the desired pulses from the undesired pulses. Normally, the rectangular pulses that are commonly employed in distance-measuring equipment and 'that are received from the beacons of the distance-measuring equipment have a wide frequency spectrum. The pulses of beacons operating on adjacent frequencies, therefore, have frequency components which fall within the pass band of the receiver being employed. Because the latter pulses do not fall fully within the frequency pass band of the receiver, they are highly differentiated while passing through the receiver and therefore normally produce pulses in the output circuit of the receiver which `have very short pulse durations.- Those adjacent carrierfrequency pulses that are -received and are very nearly within the center of the pass band lof the receiver tuned circuits are only partially differentiated so as to appear at the output of the receiver as pulses of very short duration superimposed on the top of the rectangular wave pulses. The presence of these pulses other than the desired pulses andthe facility with which at least a portion of these pulses may pass through the pass band of the receiver produce undesired and 'spurious signals in the utilization circuit of .the receiver and diminish the selectivity of the receiver to the desired pulses. It is, therefore, desirable to eliminate from within the pass band all pulses which are produced by other than pulses of desired frequency and pulse-duration characteristics.

One type of frequency/responsive network which has previously been used for such a purpose discriminates against pulses of a very short duration and passes only those pulses having a -pulse duration greater than a predetermined duration. In this type of arrangement, all pulses `of less than the predetermined desired pulse duration are eliminated but those pulses which are very close in frequency to the desired pulse, /as has been stated above, will have portions of' a very short pulse duration and portions having .a pulse duration very similar to the pulse duration of the desired pulse. Therefore, though the discriminating circuit will eliminate the short pulse-duration portions it will permit the other portions of the pulse to be translated to the utilization circuit-'even though the portionof the pulse that is-so translated has a frequency characteristic different from the desired frequency characteristic. Therefore, a disadvantage -ef this type of pulse selectivity arrangement lies in its inability completely to discriminate against all portions of the undesired pulses.

. It isl an object of this invention, therefore, to provide apulse-signal translating system which substantially avoids the disadvantage of the -prior arrangement just mentioned.

.It is 4another object of this invention to provide an improved pulse-signal translating system having a -greatly improved pulse-selectivity characteristic. It is afurther object of this invention to provide a new and improved pulse-signal ,translating systemcapable of distinguishing between de- 'sired pulses having certain desired pulse durations and undesired durations.

In accordance Witha'particular 'form of the invention, a pulse-signal translating system for translating applied desired pulses having a prepulses not having such pulse determinedpulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration 'less than the predetermined pulse duration, comprises a first repeater circuit including an input circuit responsive to 'the applied pulses and having a signal-stabilization network including circuit elements so proportioned as to cause portions of said desired pulsesforeffectingtranslation of at least a part thereof through said second repeater While saidfcontrolcircuit 'is sub stantially unresponsive toy theportions .ofeach of the undesired pulses translated by the rst repeater.

For a better understanding of the present invention, together with other and further'objects thereof, reference is had to the following descriptionv taken ini connection with `the' accompanying :dran/iria,V and its 'fscope fwill' beepointed Y out inthe appended claims.

Referring now to the drawing; Fig.'1 is 'av circuit diagram, partly schematic, of a'complete wave-signal receiver including a pulse=signal translating system embodying the presentinvention in'a particular form: Fig. 2 is a curve representingan operating characteristic of the wave-signal receiver of Fig. 1; Figs` 3 arid-ei'.`

are graphs which are utilized in explaining the operation of the pulse-signal translating system represented in Fig. 1; and Fig. 5 isa'circuit diagram of a modification of the pulse-signal translatingT system represented in'Fig. 1.

Referring now more particularly to Fig. 1 of the drawing, there is represented a pulse-signal distance-measuring receiver comprising an antenna system Iii, II for intercepting pulse-modulated carrier-freouency wave signals and for applying such signals to a radio-frequency amplifier I2 of one or more stages to which are coupled, in cascade, an oscillator-modulatorI3, an intermediate-frequency*'amplifier I4, of one or more stagesgand a detector I5. YThe selective circuits included in the radio-frequency andintermediate-frequency amplifiers I2 and I4 aresuch as efficiently to translate both the received pulseinodulated ydistance-measuring wave signal and interfering or undesired other pulse-modulated wave signals to the output circuit vof detector I5. The detector I5 is adapted to VVderive both desired and undesired pulses of a received pulsemodulated wave signal. The units I2, I3, and I4 comprise a signal-translating channel including a freouency-selective signal-translatingdevvice,-speciiically, the amplifier I2 being responsive to one group of pulses of a wave'signal of predetermined frequency in preference 'to'other groups of pulses of other wave signals of other frequencies. The amplifier I2 is adapted to translate theone-group of pulses so that they-have a predetermined pulse duration and to translate thefothergroups of pulses so that at least a portion of each thereof has a pulse duration lessi than the aforesaid predetermined pulse duration. The detector I 5 is responsive to the-pulsesy translated through the units I2, I3, and I4 for deriv- Aing from the translated pulses of the Yone 'group desired unidirectional pulses having'the aforesaid predetermined pulse'duration and for deriving from the translated pulses'of :the other groups undesired unidirectional pulses atleast a portionwor eachfof which has apulseduration less than the aforesaid predetermined pulse duration.

The receiver also includes a pulse-signal translating system embodying the present invention in a particular form. This system includes a first repeater circuit I6 and a second repeater circuit I1. The repeater circuit I6 has an input circuit .coupledto the output-circuit ,of kdetector I5 and an output circuit whichis coupled to the second repeater circuit I1. These first and second re- :peater circuits will be described in detail hereinafter.. Theoutput `circuit of the second repeater circuit II'is coupled through a condenser I9, to:afconventional utilization device 20 which mayfcomprise a cathode-ray tube indicator.

It-will -be'understood that the receiver preferably includestuned circuits, included in or preceding the detector I5, for selecting desired `pulse-inodulated carrier frequencies and for substantially rejecting undesired pulse-modulated carrier frequencies.: AThese tuned circuits may be .of-anyxtype,insofar asthe'present invention is vconcerned and manyffsuch circuits, per 'sep are well known to those skilled in the art. It is also understoodV that these circuits have the charac- .teristic of translating'desired pulses ofthe proper frequencies in a'well-known manner while translating portions of pulses having frequencies that comeV within the resonant-frequency band-in a vvhighly differentiated form. As ya result, the out- .put-circuit of detectorh I5'will include normal rectangular-wave pulses and highly differentiated rectangular-wave pulses as'appear inFig. 3 ofthe drawing.

It will also be understood that all the components of the pulse-modulated'signal receiver with exception of components Ib -and I'I may be of any suitable conventional construction and operationdetails of iwhichare Well known in the art, rendering detailed description thereof unnecessary. Considering briefly the operation of thereceiver as a whole, and neglecting for the moment i. theexact details of the pulse-signal translating system, a pulse-modulated carrierfrequency signal is'intercepted 'bythe antenna system I0, II, selected .and amplified by the `radio-frequency amplifier I2, converted to an intermediate-frequency signal by the frequency changer includingthe oscillator-modulator I3, amplified in the.intermediate-frequency amplifier I4, and detected by the detector i5, thereby to derive ,the pulse-signal modulationcomponents.; The pulse-signal components are, in turn translated vthroughthe first'repeater circuit I6,

`theesecond vrepeater circuit 'I1 and are utilized init-he devicezzc ina yconventional manner. For instance, these pulse signals may provide an indicationnf the distance between two points or, by comparison'fwith other pulse signals or the time of arrival of. otherpulse signals, may be utilized todetermine 'the directionl of an object from a commonipoint.

:Infconsideringthe' operation of the receiver arrangementisas a whole, reference is made to the series ofgraphs andcurves of Figs. 2"and 3, indicating the:receiveitresponse for the conditions in whichga'pulse-modulated wave signa-1 of desired characteristics is. intercepted by antenna system `I 0, I I while undesired pulse-modulated wave signais are also being intercepted. Fig. 2 represents the amplitudecharacteristics of radio-frequency amplifier l2 for'different carrier frequencies of pulse'wave signals. It isreadily evident that pulse 'signals having a mean frequency f are nor- `rnally translated through amplifiers I2 and I4 at Y a'very low amplitude level; pulse signals having an average mean frequency f1 are translated at a slightly higher amplitude level, while pulse signals having a mean frequency fe, being the signals of the frequency to which the radio-frequency amplifier is tuned, are translated at the greatest amplitude level. In a circuit employing normal resonant-frequency amplitude discrimination methods, the relative amplitudes between signals of mean frequency f2 and those of mean frequency f1 or f would be suiicient to discriminate in favor of the higher amplitude signals. When using resonant circuit selection arrangements for pulse signals having a wide spectrum of frequencies, this method of discrimination alone is not `sufficient as is evident from viewing the curves A and B of Fig. 3.

The curves A of Fig. 3 represent pulse-modulated carrier-frequency wave signals for the frequencies of f, fr 4and f2 of Fig. 2. Whenthese pulse-modulated carrier-frequency wave signals are passed through radio-frequency amplier I2, oscillator-modulator I3, intermediate-frequency ampliiier I4, and detector I5, they appear' at the output circuit of the detector in the form of the pulses shown in curves B of Fig. 3.

Referring again to Fig. 2, it is evident that a pulse having a mean frequency f will fail to come well within the pass band of the receiver system and, therefore, will be translated with diminished amplitude. Still, since the pulse is composed of a wide spectrum of frequencies, some of the higher frequency signals or the harmonies of the lower frequency signals will appear within the pass band. If none of the lower frequency components which form the central portion of the pulse signal fall within the pass band, only the higher frequencies which form the steep edges will pass through the pass band and appear as pulses or spikes of Very short duration in the output circuit of detector I5. These pulses are shown for the frequency f in curves B of Fig. 3. Similarly, pulses having a mean frequency of f1 will have some portions translated while other portions 'will be likewise affected by the characteristics of the resonant circuits of the receiver except that some of the lower frequency components of these pulses will pass through the pass band producing a plateau between the spike-like pulses as shown in Fig. 3. As a result, there will appear in the output circuit of detector I 5 pulses having characteristics of the type shown in curves lB of Fig. 3 for frequency f1. These pulses will have a portion of comparatively long pulse duration with highly diierentiated short duration pulses superimposed on the long duration portion. Pulses having the desired mean frequency of f2, and, therefore, occurring directly within the pass band of the receiver, will be translated in well-known manner and will appear in the output circuit of detector I5 in the form shown in curves B of Fig. 3 for frequency f2. These latter pulses have no highly dierentiated portions since they fall well within the pass band of the receiver and are not differentiated by the tuned circuits. Therefore, the pulses of the type shown in curves B of Fig. 3 for frequency f2 are desired pulses having a predetermined pulse duration, while pulses of the type shown in curves B of Fig. 3v for frequencies f and f1 are undesired pulses at least a portion of each of which has a pulse duration less than a predetermined pulse duration.

A' Referring now more particularly to the part of the system embodying the present invention, the signal-translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has pulse duration less than the predetermined pulse duration, includes a rst repeater circuit I6 which may comprise a pair of electrontube repeater devices shown as triodes ZIA and 2|B and a direct-current restorer circuit including rectier 22 and the control electrode and cathode of tube ZIA. The input circuit of repeater I3 is coupled to the output of detector I5 through a condenser 23. This input circuit includes the rectier 22 and the load circuit comprising a radio-frequency choke 24 and a resistor 25. The control electrode of tube 2|A is connected to the junction of radio-frequency choke 24 and resistance 25 and is normally at ground potential when no current is flowing in the resistor 25. The cathode of the tube 2|A is degeneratively connected to ground through resistor 26, and is normally at a slightly positive potential with respect to ground. The resistors 25, 2S, the choke 24, and the condenser 23 with the cathode and control electrode of the tube 2 IA comprise a signal-stabilization network in which the elements 23--26, inclusive, are so proportioned as to cause the peaks of the pulses applied to the control electrode of the tube 2 IA to be stabilized at the same potential. The value of the bias on tube 2|A is so proportioned as to translate only a portion of each of the undesired pulses exceeding a selected amplitude level while translating atleast a portion of the desired pulses exceeding a selected amplitude level. The rectier 22 is adapted to stabilize the pulses with respect to ground potential. The anode of tube 2|A is connected to a source of potential +B through a load resistor 21 and the output circuit of this tube is coupled from this anode through a condenser 28 to the control electrode of tube 2|B. The latter control electrode is also connected through a load resistor 29 to a source of potential -l-C. The cathode of tube ZIB is connected to ground while the anode is connected through a radio-frequency choke I8 and timedelay network 32 to the second control electrode of tube 3|. Condenser 30 is connected between the junction of choke I8 and network 32 and ground. The first control electrode of tube 3| is `also connected to the junction of choke I8 and network 32. The circuits of tube 3| form a coincidence mixer arrangement. Time-delay network 32 is proportioned to have a delay time suinciently long to block short duration pulses in the tube 3| while permitting portions of longer duration pulses to be translated therethrough.

The time-delay network 32 and the tube 3| form a second repeater circuit coupled to the rst repeater circuit which is so proportioned as to translate desired pulses of a predetermined duration while being unresponsive to the portion of each of the undesired pulses translated by the rst repeater. The screen electrode of tube 3| is connected to a suitable source of positive potential indicated -i-Sc, while the cathode of the same tube is connected through condenser 33 to ground and through a resistor 36 to a'suitable source of positive bias indicated +C. This cathode is also connected through a resistor 34 to the second control electrode of this tube to provide a cutoff bias for this electrode. The anode of tube 3| is connected through a load resistor 35 to a source of potential +B and through condenser I9 to the utilization device 2D. The network 32 and the biasing resistors 34 and 36 compr-lse; a control circuit for fcontrollingVV the. conductivity ,of the tube. 3i

Considering now inparticularthe,operation of the pulse-signal translating systemportion of the receiver including first repeatercircuit i6 and second repeater circuit Il, the curves A-E of Fig. 4, are especially helpful. Curves kA of Fig. 4; show thesamepulseforrns appearingin the output circuit of detector I5 Vfor carrier frequencies f, f1 and f2 as didcurves B of Fig. 3. It yis desiredtotranslate pulse forms having a predetermnedpulse duration as shown inV curves` A of Fig;` 4 for frequency f2 while discriminating againstundesired pulses at least a portion of each of -ivhich has-pulse duration less than the predetermined pulse duration as shown in kcurves A of Fig. 4 for frequencies f and f1. It is to be understood that the pulses appearing at this pointin the receiver circuit may have different relative amplitudes and may also have different average voltages with respect to ground or zero voltage. As the pulses having mean frequencies fr and f2 and represented in curves A of Fig. l are translated through condenser 23 and are impressedacross rectifierv vand onto the control electrode oftube 25A, they assume the forms shownfin curves B of Fig. 4 having been stabilized at their points of highest amplitude with respect to a reference level formed bythe potential at which thecontrol electrode of tube IA' draws current. Tube'ZiAA is normally at cutoff. That part of each positivepulse applied to the control electrode of this tube Y which ,hasl potential .levels between the positive biaspotential of the tube approximately +C, and.; thecutoi potential of the tube, approximately Zero or ground potential on the control electrode, will be translated therethrough. The remaining positive part of'each pulse causescurrentto flow between the -cathode and control electrode of the tube and is not translated. Therefore, the topof each pulse is arranged to have an equal-potential above zero or ground. When the down orl negative swing of the pulse or spike occurs, a negative potential would be developed acrosschoke 2I` and-resistor 25.which would be equal innegative potential to the amount by which the positive potential of the pulse exceeded the positive bias ofthe tube, if rectifier 22 was not-in the circuit. This part of the pulsesis shown by the dotted linesof'curves B of Fig. 4. I n practice, rectifier 22 eliminates this negative swing and thereby effects quick recovery of the circuit. Therefore, the electron tube repeater stage including tube EIA is seen to be so proportioned by having the control electrode of tube ZIA properly biased that only a small selected amplitudelevel portion of the high amplitude part of the pulses is translated therethrough, the pulses appearing in the output oircuit ofthe triode having the forms shown in curves C of Fig. 4. In examining the pulses showninthecurves of B and C of Fig. 4, it now becomes evident that the three pulse formsshown incurves A have been converted into two pulse forms; undesired pulses at frequencies f and f1 having. pulse durations-less than a predetermined pulse duration, and desired pulses at the frequency f2 having a predetermined pulse duration. These pulses are then translated through tube 2 IB, being amplied and inverted therein, and appear across condenser 30 at the input circuit of tube 3l as positive pulses of the forms shown in curves D of Fig. 4. As has been stated above, the circuits of tube 3| are. so proportioned by means of time-delay network 32 and the presence of--acutoif bias Onboth the flrst'andfsecond oontrol electrodesfthatthis tube is normallyat cutoff condition producing no output signal. A positive potential signal appearing on the biased control electrode ofthis tube will tend to cause the tube to conduct, but the bias on the second control electrode will p revent such conduction unlessa positive signalyof sufficient strength also appears on this electrode simultaneously with the appearance of the signal on the control electrode. By employing time-delay means 32 in the secondcontrol grid circuit and so proportioning it as to have a time delay greater than the time duration of the shortest duration of a pulse which it is desired to translate, all pulses of shorter duration are automatically blocked. Therefore, undesired pulses having pulse durations less than a predetermined pulse duration are blocked by the functioning of coincidence mixer 3| while desired pulses having at least a pulse duration greater than the predetermined value of timedelay means 32 willyat least be partially translated and passed through coupling condenser i9 into utilization device 2t as shown by curve E of Fig. 4. Therefore, it is seen that a pulse-signal translating system is provided which will translate applied desired pulses having a predetermined pulse duration and which will discriminate against applied undesiredv pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration.

The following circuitpccnstants have been used in one embodiment of the invention constructed in accordance with the arrangement described in Fig. 1 Resistors 25 and 29 0.4!! megohm. Resistor 25 100 ohms, Resistor 2': 10,000 ohms. Resistor 35 47,000 ohms. Resistor 34 1,500 ohms. Resistor 35w 15,000 ohms. Condenser 23 1,000 micromicrofarads. Condenser 30 47 micromicrofarads. Condenser 33 0.5 micromicrofarad.

, Inductors 24 and I8 lZ'microhenries. Time-delay network 32 0.50 microsecond time delay.

Tubes 2 IA and 2 IB Type l2AT7 duotriode. Tube 3I Type GASS. Rectier 22 Crystal rectifier' 1N34. -I-B potential volts. -i-C volts Referring now to Fig. 5 of the drawing, there-is represented schematically a modied form of the pulse-signal translating system of Fig. l and embodying this invention. The circuit of Fig. 5 may readily be employed' inthe receiver of Fig. l by replacing first repeater circuit I6 in that receiver with the rst repeater circuit shown in Fig. 5. Since the modified form of first repeater circuit |51 is similar to that of Fig. l, corresponding circuit elements are identified by identical refer-- ence numerals while similar circuit elements are identied by the saine reference numeralsprimed. In Fig. 5, the firsty repeater circuit comprises a diode rectifier Mll adapted to be coupled across the output circuit of the detector I5 through the condenser 23 and a load resistor 42. This rectier comprises a signal-level stabilization circuit for stabilizing pulse signals with respect to a reference level. The cathode of rectier 40 is also directly connected to the control electrode of electron repeaterV tube 2IA1. An additional rectifier 4I is connected between this control electrode and a suitable sourceof slightly positive assistive bias, the anode of the rectier being connected to the control electrode while the cathode is connected to the source of bias. Rectiiier 4l comprises a circuit for so biasing electron repeater tube ZIAl that at least a portion of each of the desired pulse signals having a predetermined pulse duration will be translated while only a portion of each of the undesired signals having portions thereof of less than a predetermined pulse duration will be translated. Except for changes in the connection of the control electrode, electron repeater tube 2lA1 is connected in a similar manner to tube 2 iA of Fig. 1. There are no changes in the connections or circuit constants of tube 2IA1. Therefore, the detailed connections of tubes 2lA1 and 2231 will not be described with reference to the embodiment of this figure.

'I'he operation of the first repeater circuit 61 of Fig. 5 is similar to the operation of repeater circuit IS oi Fig. l except for the functioning of rectier si. In the repeater circuit of Fig. l, the control electrode of tube 2 IA derives its bias from the load circuit including radio-frequency coil 24 and resistor 25 and acts in the capacity of a diode when signals of greater than a predetermined signal strength are being translated. In the repeater circuit of Fig. 5, the diode function is provided by means of rectier 4| which is so proportioned as to conduct in the presence of signals of greater than a predetermined signal strength, thereby stabilizing pulses with respect to the top portions of the pulses. Functioning of a diode rectifier as a stabilizer is well known and will not be described herein in detail. The curves of Fig. 4 are applicable to the operation of the arrangement shown by Fig. 5, and the description of these curves presented above Will also suilice to describe the operation of the circuit of Fig. 5.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modiications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fail within the true spirit and scope of the invention.

What is claimed is:

l. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a rst repeater circuit including an input circuit responsive to said applied pulses and having a signal-stabilization network including circuit elements so proportioned as to cause the peaks of said applied pulses to be stabilized at the same potential for effecting translation of only a portion of the peak amplitude of each of said undesired pulses and the translation of at least a portion of the peak amplitude of each of said desired pulses through said first repeater circuit; and a second repeater circuit coupled to said rst repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to said translated portions of said desired pulses for eiecting translation of at least a part thereof through said second repeater while said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said first repeater.

2. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a first repeater circuit including an input circuit responsive to said applied pulses and having a signal-stabilization network including circuit elements so proportioned as to cause the peaks of said applied pulses to be stabilized at the same potential for effecting translation of only the peak amplitude of said portion of each of said undesired pulses which has a pulse duration less than said predetermined duration and the translation of at least a portion of the peak amplitude of each of said desired pulses through said first repeater circuit; and a second repeater circuit coupled to said first repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to said translated portions of said desired pulses for effecting translation of at least a part thereof through said second repeater while said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said first repeater.

3. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a rst electron-tube repeater circuit including a cathode and a control electrode responsive to said applied pulses and a signal-stabilization network coupled between said cathode and said control electrode for causing the peaks of said applied pulses to be stabilized at the same potential and for causing said control electrode to have such a negative polarity with respect to said cathode as to cause said repeater circuit to be nonconductive except for the translation of only a portion of each of said undesired pulses exceeding a selected amplitude level and except for the translation or" at least a portion of each of said desired pulses exceeding a selected amplitude level through said first repeater circuit; and a second repeater circuit coupled to said rst repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to said translated portions of said desired pulses for electing translation of at least a part thereof through said second repeater while said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said first repeater.

4. A pulse-signal translating system for translating applied desired positive-going pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a iirst electron-tube repeater circuit including a cathode, a control electrode and an anode responsive to said applied pulses and including a signal-stabilization network coupled between said cathode and said control electrode for causing the peaks of said applied pulses to be stabilized at the same potential and for causing said control electrode to have such a negative polarity with respect to said cathode as to cause said repeater circuit to be nonconductive except for the translation of only a portion of the peak amof atleast a portionor.. the peak amplitude of each of said desired pulses translated portions of said pulses; and a second. Y

repeater circuit coupled to said phase-inverter` circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuitbeing responsive to said inverted portions of said desired pulses for electing translation thereofv through said second repeater while said control circuit is substantially unresponsive to the inverted portion of said each of said undesired pulses translated by said phaseinverter circuit.

5. A pulse-signal translatingvsystem for translating applied desired pulses ,having a predeter-.

mined pulse duration andv for discriminating against applied undesired pulses at least a por-V tion of each of which has .a pulse duration less` than said predetermined pulse duration compris-v ing: a rst repeater circuit,..including Yan input circuit resp-onsive to said applied pulses and hav-- ing a signal-stabilization network including circuit elements so proportioned as to cause the peaks of said applied pulses .to lie-stabilized at the same potential foreffecting translation of only a portion of the peak amplitude of each or, said. undesired pulses `and the translation of at least a portion of the peak amplitude of each of said desired pulses throughisaid iirstj repeater circuit; and a coincidence mixer circuit coupled to said rst repeater circuit and including a control circuit for controlling the conductivity of said coincidence mixer circuit ysaid control circuit being responsive to said translated portions of said desired pulses for effecting translation of `at least a part thereof through saidcoincidence mixer while said control circuit is vsubstantially unresponsive to the portion of said each of said undesired pulses translated bysaid rst repeater.

6. A pulse-signal translatingY system for translating applied desired positive-going pulses having a predetermined criminating against .applied .undesired tion less than said predetermined pulse duration comprising: a ilrstelectron-tube repeater cirpulse duration and for dispulses at least a p-ortion of each of which has a pulse dura-.-

signal-stabilization networkcoupled.between said p cathode and said control. electrode for causing the peaks oi said applied pulses to be stabilized at the same potential andforcausingsaid control electrode to have such a negative .polarity with respect to said cathode as to cause said repeater circuit to be nonconductive except for the translation of only a portion of the peak amplitude of each of said undesired pulses and except for the translation of at least a portion of the peak amplitude of each of 'saidvdesired pulses.

through said rst repeater circuit; a second electron-tube repeater circuit including a cathode and a pair of control electrodes coupled to said rst repeater circuit; anda biasing resistor network coupled between said last-mentioned cathode and at least one of said last-mentioned control electrodes for causing said one of said lastrnentioned control velectrodes to havesuch a negative polarity with respect to said last-mentioned cathode as to cause said secondrepeater circuit to benonconductive -except for the translation therethroughof said translated portions of .said f desired pulses.

'7. A pulse-signal translating system for translating applied desired positive-going pulses having a predetermined pulse duration and for dis.. criminating against applied undesired pulses. at i least a portion ci each of which has a pulse duration less than said predetermined pulse dura-y tion comprising: a nrst electron-tube repeater circuit including a cathode and a control electrode responsive to said applied pulses and including a signal-stabilization network coupled between said cathode and said control electrode for causing the positive peaks of said applied pulses to be stabilized at the same potential and for causing said control electrode to have such a negative polarity with respect to said cathode as to cause said repeater circuit to be nonconductive except for the translation of only a portion of the peak amplitude of each of said un desired pulses and except for the translation of at least a portion of the peak amplitude of each of said desired pulses through said first repeater circuit; and a second electron-tube repeater circuit including a cathode and a pair of control electrodes coupled to said first repeater circuit, a time-delay circuit coupled between one of said last-mentioned control electrodes and said first.

repeater circuit and a biasing resistor network coupled between said last-mentioned cathode and the other of said last-mentioned control electrodes for causing at least said other of said last-Y mentioned electrodes to have such a negative bias with respect to said last-mentioned cathode.

as to cause said second repeater to be nonconductive except for coincidence of signals on said last-mentioned control electrodes, thereby.

to translate through said second repeater said translated portions of said desired pulses.

8. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a por.

tion of each of which has a pulse duration less than said predetermined pulse duration comprising: a rst repeater circuit including an input circuit responsive to said applied pulses and having a signal-stabilization network including circuit elements so proportioned as to cause the peaks of saidapplied pulses tobe stabilized at the same potential forv effecting translation of only a portion of the peak amplitude of each of said undesired pulses and the translation of at least a portion of the peak amplitude of each of said desired pulses through said first repeater circuit; and a second repeater circuit, including a time-delay circuit, coupled to said rst repeater circuit and including a biasing circuit so proportioned as to bias said second repeater circuit to cutoi by a biasing potential which is exceeded by the amplitude of said translated portions of said desired pulses translated through said time-delay circuit and applied to said vbiasing circuit thereby to translate said translated portions of said desired pulses but to be substantially unresponsive to the portion of said each of said undesired pulses translated by said first repeater.

9. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminatingl the translation of at least a portion of the peak amplitude of each of said desired pulses through said first repeater stages; and a second repeater stage coupled to said electron-tube repeater stage and including a control circuit for controlling the conductivity of said second repeater stage, said control circuit being responsive to said translated portions of said desired pulses for effecting translation of at least a part thereof through said sec.

ond repeater While said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said electron-tube repeater stage.

l0. A pulse-signal translating system for tran. lating applied desired positive-going pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of Which has a pulse duration less than said predetermined pulse duration comprising: a diode rectifier circuit to which said pulses are applied being so biased as to stabilize said pulses with respect to a predetermined reference level; an electron-tube repeater stage coupled to said rectier stabilization networkincluding circuit elements so proportioned as to cause the positive peaks of said applied pulses to be stabilized at the same potential for effecting translation of only a portion of each of said undesired pulses exceeding a selected amplitude level and the translation of at least a portion of each of said desired pulses exceeding a selected amplitude level through said electron-tube repeater stage; and a second repeater stage coupled to said electrontube repeater stage and including a biasing eircuit so proportioned as to bias said second repeater stage to cutoff by a biasing potential which is exceeded by said translated portions of said desired pulses thereby to translate said translated portions of said desired pulses but to be substantially unresponsive to the portion of said each of said undesired pulses translated by said electron-tube repeater stage.

1l. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired'pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a signal-level stabilization circuit to which said pulses are applied being so proportioned as to stabilize said pulses with respect to a predetermined reference level; an electrontube repeater circuit coupled to said stabilization circuit and having a signal-stabilization network including circuit elements so proportioned as to cause the peaks of said applied pulses to be stabilized at the same potential for effecting translation of only a portion of the peak amplitude of each of said undesired pulses and the translation of at least a portion of the peak amplitude of each of said desired pulses through said iirst repeater circuit; and a second repeater circuit coupled to said electron-tube repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to said translated portions of said desired pulses and having a signal- 14 for effecting translation of at least a part thereof through said second repeater while said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said rst repeater.

12. A pulse-signal translating system for translating applied desired pulses having a predetermined pulse duration and for discriminating against applied undesired .pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a signal-level stabilization circuit to which said pulses are applied being so biased as to stabilize said pulses with respect to a predetermined signal voltage reference level; an electrontube repeater circuit coupled to said stabilization circuit and including a signal-stabilization network so proportioned as to cause the peaks' of said applied pulses to be stabilized at the same potential and to bias said cutoff except for the translation of only the peak amplitude of said portions of each of said undesired pulses which have pulse durations less than said predetermined duration and the translation of at least a portion of the peak amplitude of each of said desired pulses which have a predetermined pulse duration; and a second repeater circuit coupled to said translated portions of said electron-tube repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to said translated portions of said desired pulses for eiecting translation of at least a part thereof through said second repeater While said control circuit is substantially unresponsive to the portion of said each of said undesired pulses translated by said rst repeater.

13. A pulse-signal translating system for translating applied desired positive-going pulses having a predetermined pulse duration andfor discriminating against applied undesired pulses at tude of each of said desired pulses; and a secondA amplifier coupled to said rst amplifier and including a biasing circuit being so proportioned as to bias said second amplifier to cutoi by a biasing potential which is exceeded by said translated portions of said desired pulses thereby to translate some pulse durations oi' said translated portions of said desired pulses but to be substantially unresponsive to the portion of said each of said undesired p-ulses translated by said rst ampliiier.

14. A pulse-signal translating system for translating applied desired positive-going pulses having a predetermined pulse duration and for discriminating against applied undesired pulses at least a portion of each of which has a pulse duration less than said predetermined pulse duration comprising: a rectifier circuit to which said pulses are applied being so biased as to eliminate all so proportioned as to eiiect grid current stabili-,-

repeater circuit to,

sation 'ofsaid pulses with respect Ato apredeterminedreference level and which translates only a portion of the peak amplitude .of each of said undesired pulses While being eiective to translate at least a portion of the peak amplitude of each of said desired pulses; 'and a second amplifier coupled to said first ampliiier and including a biasing circuit being so 'proportioned as to bias said second ampliiier to'cuto by aA biasing potential which is exceeded by said translated-portions of said desired pulses therebyto translate some pulse durations of said translated portions ofV said desired pulses but t be substantially unresponsive to the portion of said each of said undesired pulses translated by said first ampliiier.

15. A pulse-signal selection system for selecting one group `of pulses of a wave signal of predetermined frequency in preference to other groups of pulses of other wave signals of other frequencies comprising: a signal-translating channel including a frequency-selective signaltranslating device responsive to said one and said other groups of pulses for'translating said one group of pulses so that they have a predetermined pulse duration and for translating said other groups of pulses so that at least a portion of each pulse has a pulse duration less than said predetermined pulse duration; a detector coupled to said channel and responsive to said translated pulses for deriving 'from said translated pulses of said one group desired unidirectional pulses having said'predetermined pulse duration and for deriving from said translated pulses of said other groups undesired unidirectional pulses at least a portionfof each of Which has a pulse duration less than said predetermined pulse 'duration; a rst repeater circuit including an input circuit coupled to said detector and responsive to said derived pulses and having a signal-stabilization network including circuit elements so proportioned as to cause the peaks of said derived pulses to be stabilized at the same potenw tial for effecting the translation through said first repeater circuit of only a portion of the peak amplitude of each of said undesired pulses and the translation of at least a portion of each of said desired pulses; and a second repeater circuit coupled to said first repeater circuit and including a) control Acircuit for controlling thev conductivity of said second repeater 'circuit said control` circuit being responsive to saidr translated portions of said desired pulses for effecting translation thereof through said second repeater While `said control circuit is substantially unresponsive to the portion of each of said undesired pulses translated by said first repeater.

16. A pulse-signal selection system for selecting one group of pulses of a wave signal of predetermined frequency in preference to other groups of pulses of other Wave signals of other frequencies comprising: a signal-translating channel including a radio-frequency amplifier responsive to said one and said other groups of pulses for translating said one group of pulses so that they have a predetermined pulse duration and for translating said other groups of pulses so that at least a portion of each or which has a pulse duration less than said predeter mined pulse duration; a detector coupled to said channel and responsive to said translated pulses for deriving from said translated pulses of said one group desired unidirectional pulses having said predetermined pulse duration and for deriving from said translated pulses of said other groups vundesired vunidirectionalpulses" atleast a portion 'of each of which has a pulse duration less than said predetermined pulse duration; a iirst repeater circuit including an input circuit coupled to said-detector-and responsive rto said derived pulses vand having a signal-stabilization netWork--including circuit velements. so proportionedras -to cause the peaks of said derived pulses to be stabilized at the 'same potential for effecting the translation of only aportion of the peak amplitude-of each of said undesired pulses and thetranslation of at least a portion'of each ofsaid desired pulses through said iirst repeater circuit; `and a second repeater circuit coupled to said 'first repeater circuit and including a control circuit for controlling the conductivity of said second repeater circuit said control circuit being responsive to'said translated portions of said desired pulses forV effecting translation thereof through said second repeater while said control circuit is substantially unresponsive to the portion of each of said undesired 'pulses translated by said first repeater.

17. A' pulse-signal selection system for' selecting one group of pulses of a wave signal of predetermined frequency'f'in preference to other groups of 'pulses of other wave signals of other frequencies comprising: a signal-translating channel including" a radio-frequency `amplifier tuned to said predetermined frequency and responsive to said one and Asaid other groups of pulses for translating'said one' group of pulses so that they have a predetermined pulse duration an-d for translating said other'groups of pulses so that atleast a portion of each of which hasl a' pulse. duration v'lessi 'than said predetermined pulse duration; a detector coupled to said channel and responsive to said translated pulses for deriving from said translated pulses Aof said one group desired unidirectional pulses having said predetermined pulse duration and for deriving from said translated pulses of said other groups undesired unidirectional'pulses at least a portion of each "of whichhas a vpulse 'duration less than said predeterminedpulse duration; a rst repeater circuit including 'an input circuit coupled to said detector and. responsive to said derived pulses' and having a signal-stabilization network including circuit'v elements so proportionedas to cause thepeaks of -Asaid derived pulses to be stabilized atthe same potential for effecting the translation-of only a portion of the peak amplitude 'of each 'of said undesired' pulses and'the'translation of 'at least a portion of each of said' desired pulses through said first repeater circuit; and-a second repeater circuit coupled to said iirstrepe'ater circuit and including a control circuit for controlling the conductivity of said second repeater circuit-said control circuit being responsive to saidf translated portions of said desired pulses forv effecting 'translation thereof through said secondrepeater while 'said control circuit is substantially unresponsive to the portion of each of said undesired pulses'translated by said first repeater.

ROBERT B. J. BRUNN.

References 'Cited'.in` thele 0f this patent UNITED STATES PATENTS Number Y Name Date 2,211,942 White Aug. 20, 1940 2,434,937 Labin V.- Jan. 27, 1948 2,484,352 Miller et a1 Oct. '11, 1949 2,534,264 Hoeppner Y Y.-.v- -Dec. 19, 1950 2,579,473 Chatterjea Y -v r Dec. 25, 1951 

